Preheat oven to 400 degrees F. Line a tray with approximately 32 baking cups. Sift the flour with the salt and split them into two portions.
Beat the butter and sugar in a stand mixer until light and fluffy.
Add the lavender seeds from the dried flowers and beat again. Add one half of the flour and beat well until fluffy.
Mix in the other half of the flour and beat for 3 minutes. Use an ice cream scoop or a tablespoon, and spoon out a small ball of the mixture.
Roll into balls using your palms and put each ball into a baking cup and press down in the center to form a depression for the jam with your thumb. Bake the tarts for 10 minutes.
Allow the tarts to cool. Put a little jam in the center and dredge with icing sugar after they have cooled. Serve with espresso coffee or tea.
Notes
You need baking cups for this recipe, but you could still use small madeleine molds or muffin trays that are greased.
Raspberry, strawberry or cherry jam will be fine in lieu of grape.
You can substitute vanilla or almond essence for the lavender essence or flowers.